[FFmpeg-user] Encoding multiple files for adaptive bit rate streaming using RTMP and HLS

[Henk D. Schoneveld]

On 12 May 2015, at 16:32, Henk D. Schoneveld <belcampo at zonnet.nl> wrote:

> 
> On 12 May 2015, at 15:50, Werner Robitza <werner.robitza at gmail.com> wrote:
> 
>> On Tue, May 12, 2015 at 3:16 PM, Henk D. Schoneveld <belcampo at zonnet.nl> wrote:
>>> 
>>>> On 12 May 2015, at 13:50, Werner Robitza <werner.robitza at gmail.com> wrote:
>>>> 
>>>> On Tue, May 12, 2015 at 11:47 AM, Henk D. Schoneveld <belcampo at zonnet.nl> wrote:
>>>>> Would you be so kind to explain why to NOT use the crf option?
>>>> 
>>>> CRF is essentially a constant quality mode, which results in variable
>>>> bitrate depending on the spatiotemporal complexity of the scenes.
>>> Your goal is max quality within a given link-capacity I assume.
>>> Upfront choosing an arbitrary bitrate to achieve max possible quality seems sub-optimal/contradictionary to me.
>>> A. to many bits for talking heads
>>> B. to few bits for action dominant events.
>> 
>> Yes, but that's still what's typically done, unless you choose a CQ
>> encoding type with a max-rate (which is what libvpx recommends too).
> But libvpx is much less efficient than libx264 for the same quality.
>> 
>> You should've mentioned that you're experienced with this -- otherwise
>> I would've given a different answer.
> Hm what difference does it make if I know a little bit more or less to how/what you’re answering ?
> Another option to ‘optimise’ quality for a given bitrate is to use anamorphic encoding. I know YouTube doesn’t accept that but all modern players I know of handle it without any problem.
> For 720p I use -s 880x720 which works for me pretty well. With this you’ll get a reduction of (1280-880)/1280=31% in needed bits for very reasonable quality. At least a lot better then reducing the bitrate by that % and using 1:1 ie. -s 1280x720 encoding.
Test results by doing as forementioned
2442734 May 12  2015 Source_Code-crf22-1280.mp4
1656672 May 12  2015 Source_Code-crf22-880.mp4
2045725 May 12  2015 Source_Code-crf23-1280.mp4
1403091 May 12  2015 Source_Code-crf23-880.mp4

This are video only files.
>> 
>>> I see the difference between the methods, but I don’t really understand what it’s trying to tel me. What does the X-axis say, total stream-size/#frames/ ?
>> 
>> It's the frame number (index) in a 3 minute sequence.
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